Abstract: A method of creating an application definition for a distributed application is disclosed. Constructs corresponding with a schema of the distributed application are defined in a declarative and technology agnostic manner. The constructs include the application definition, a module definition, and a component definition. Each construct includes metadata.

Abstract: An application on a device may interact with a document service that provides access to a document service. The interaction may occur in a variety of contexts, such as a device context (e.g., the document service and the application provided on the same device), a local context (e.g., via a LAN), and a remote context (e.g., over the Internet). It may be advantageous to adapt the interaction to the current context, while also providing a consistent application interface that alleviates the application from context-specific implementations, and also achieving this adaptation in a performant manner. These considerations may be achieved in a balanced manner by providing a set of runtimes, where each runtime mediates the application/document service interaction between the application and the document service in a contextually adapted manner. The device may automatically detect the context of the interaction and select a contextually suitable runtime to service the application.

Abstract: The management of applications in a computing environment often involves a significant number of computing operations, such as acquiring the application, deploying data objects in various locations, and configuring the application with respect to the deployed device. Conventional computing environments may provide inadequate support throughout a typical application life cycle, especially for a computing environment distributed across many devices. Instead, the computing environment may be represented in a deployable object hierarchy that may be distributed to various devices. An application management service may therefore be provided to install representations of the application in the object hierarchy, and to support many other aspects of the application life cycle, such as application discovery, sharing, updating, and removal.

Abstract: Databases are often provided according to various organizational models (e.g., document-oriented storage, key/value stores, and relational database), and are accessed through various access models (e.g., SQL, XPath, and schemaless queries). As data is shared across sources and applications, the dependency of a data service upon a particular organizational and/or access models may become confining. Instead, data services may store data in a base representation format, such as an atom-record-sequence model. New data received in a native item format may be converted into the base representation format for storage, and converted into a requested format to fulfill data requests. Queries may be translated from a native query format into a base query format that is applicable to the base representation format of the data set, e.g., via translation into an query intermediate language (such as JavaScript) and compilation into opcodes that are executed by a virtual machine within the database engine.

Abstract: Data services are often provided with various performance guarantees. Multi-master architectures, in which multiple master servers are permitted to update a portion of the data set, may facilitate some performance requirements, but may also lead to data version conflicts in which different masters have written different versions of one or more data items. Moreover, conflicts involving different data items may have to be resolved using different conflict resolution techniques. Therefore, various data items of the data set may be associated with a conflict resolution technique selected from a conflict resolution technique set, such as manual conflict resolution; a write order policy, such as last writer wins; a conflict resolution logic; and conflict resolution based on data types. A data version conflict may be resolved by identifying and invoking the selected conflict resolution technique that is associated with the data item, and applying the conflict resolution outcome to the data item.

Abstract: Processing services are often provisioned by defining and adjusting the performance capabilities of individual servers, and in multitenancy scenarios, servers may allocate computational resources to ensure that a first client workload does not impact a second client workload. However, a reduced performance capability of a server may create a processing jam with respect to an upstream server of the process path of the workload, where the processing rate mismatch creates a risk of failing to fulfill the performance guarantee for the workload. Instead, the downstream server may monitor and compare its performance capability with the performance guarantee. If a performance guarantee failure risk arises, the server may transmit a performance capability alert to the upstream server, which may rate-limit the processing of the workload. Rate-limiting by the first server in the server path may limit workload intake to a volume for which the process path can fulfill the performance guarantee.

Abstract: Data services for workloads are often provided with a service level agreement specifying various performance guarantees (e.g., latency, availability, scalability, and consistency). Single-master architectures, in which updates to the data set are constrained to a single server, may limit the fulfillment of some performance guarantees. Presented herein are multi-master architectures, in which the server set is partitioned into at least two masters are permitted to update the data set and at least one non-master that is not permitted to update the data set. Non-masters that receive a request to update the data set forward the request to a master server for application to the data set. A master that receives the request applies it to the data set and propagates the update to other master and non-master servers. Conflicting updates may be resolved through a variety of conflict resolution techniques, optionally designating one master server as a conflict resolution server.

Abstract: Workloads are often performed by a server set according to a service level agreement, and are often provisioned and load-balanced by dedicating selected computational resources (e.g., servers and bandwidth) for application to the workload. However, resource-based provisioning may not accurately reflect the computational resource expenditure of the workload, leading to overprovisioning or underprovisioning of servers for the workload. Instead, the workload may be evaluated according to a service unit as a measurement of a volume of computational resources consumed by a workload unit, including performance dimensions specified in the service level agreement. The service level agreement may indicate a service unit rate for the workload. The workload may therefore be allocated to a subset of servers in portions according to a service unit rate, where the sum of the service unit rates for the portions allocated to the servers satisfies the service unit rate specified in the service level agreement.

Abstract: Data services are often provided with consistency guarantees of either strong consistency models, comprising uniform wall-clock consistency, or eventual consistency models, where temporary logical inconsistency is guaranteed to be resolved only after full data propagation. However, the performance characteristics of contemporary services often require an intermediate consistency model, where some aspects of the service have specific consistency expectations and other aspects of the service are flexible, such as bounded staleness (e.g., a maximum delay in reaching consistency); session consistency (e.g., individual sessions remain logically consistent, but ordering may vary across sessions); and prefix consistency (e.g., each view during a session is logically consistent, but ordering may vary between session views).

Abstract: Distributed transactions are performed over a collection of servers operating as replicas of a data set, where a successful transaction involves meeting a quorum count of replicas that locally commit the transaction. However, performance constraints of data sets and consuming applications may vary (e.g., sensitivity to latency, scalability, and/or consistency), and the performance characteristics of the server set may be partly determined by the transactional commitment and quorum selection. The distributed transaction may be applied by designating the replicas as a set of followers and a leader that initiates the transaction and receives acknowledgments of local commits by each follower. On condition of the acknowledgments meeting a quorum count for the data set according to the performance characteristics of the application, the leader locally commits the transaction and delivers a result.

Abstract: A data service may be distributed over a set of servers in order to provide a database with properties such as low latency, high availability, and support for various consistency levels. Presented herein is a particular architecture that promotes rapid provisioning to promote scalability and failover; adaptive load-balancing to accommodate fluctuations in demand; and resiliency in the event of various types of failure, such as network partitions or regional outages. For a service comprising a resource set, a container is provided that hosts a set of replicas of a partition, and that is assigned an allocation of computing capabilities of one or more servers. The resource set of the service may be distributed over the replicas of the container. Scalability is achieved by adding replicas to the container, and load-balancing may be provided by splitting, merging, or otherwise refactoring the partition to accommodate anticipated and unanticipated fluctuations in service demand.

Abstract: Data sets such as databases are often distributed over a number of servers, where each server stores a subset of records and an index that enables the server to locate the records in response to queries. However, tight coupling of indexing and storage may limit load-balancing, fault recovery, and distribution. Instead, the set of servers may be partitioned into a set of storage servers that store the records and a set of index servers of the index over the records. In a set that is decoupled in this manner, load-balancing may involve provisioning and locating index servers independently of the provisioning and locating of the storage servers in view of the particular sensitivities and tolerances of various applications. Additionally, the index servers may also utilize a data layout that is selected and adapted independent of the data layout of the storage servers and/or the schema of the data stored thereby.

Abstract: A server set for a data set may designate a subset of “master” servers that update the data set in order to reduce data version conflicts involving mutually exclusive updates of the data set. Multi-master configurations may fulfill the performance constraints, and the subset of masters may detect and resolve data version conflicts. However, if multiple masters perform conflict resolution for a particular data version conflict, the resolution may produce inefficiency and redundancy (if the masters reach the same outcome) or additional data version conflicts (if the masters reach different outcomes). Instead, among the masters, a merge master may be identified that applies conflict resolution techniques to data version conflicts and forwards the conflict resolution outcome to the other masters for application to the data set to resolve the data version conflict. The other masters may temporarily store updates in a tentative update set until data version conflicts are resolved.

Abstract: Systems and methods according to various embodiments disclose a worker process manager adapted to spawn one or more worker processes on a server and to load an application on each of the worker processes. The worker process manager is adapted to isolate the one or more worker processes from each other and to control resource usage by the worker processes. A resource manager is adapted to detect applications that overuse system resources. The worker process manager is adapted to isolate worker processes and to control resource usage using one or more of the following techniques: least-privilege execution, messaging isolation, credentials isolation, data isolation, network isolation, fair share resource usage, and managed runtime security. Heuristic algorithms are used to detect applications that frequently overuse system resources that are unchargeable and that cause system unresponsiveness.

Abstract: An application on a device may interact with a document service that provides access to a document service. The interaction may occur in a variety of contexts, such as a device context (e.g., the document service and the application provided on the same device), a local context (e.g., via a LAN), and a remote context (e.g., over the Internet). It may be advantageous to adapt the interaction to the current context, while also providing a consistent application interface that alleviates the application from context-specific implementations, and also achieving this adaptation in a performant manner. These considerations may be achieved in a balanced manner by providing a set of runtimes, where each runtime mediates the application/document service interaction between the application and the document service in a contextually adapted manner. The device may automatically detect the context of the interaction and select a contextually suitable runtime to service the application.

Abstract: A server set may provide a document service to various clients in view of considerations such as availability, fault tolerance, flexibility, and performance. Presented herein are document service architectures that involve partitioning the document set into at least two document ranges, and assigning the respective document ranges to an agent that is deployed to at least one assigned server. A request to apply an operation to a selected document may be fulfilled by identifying the document range of the document; identifying a selected server of the server set that hosts the agent to which the range is assigned; and forwarding the request to the selected server. In some variations, servers may retain detailed information about neighboring servers (e.g., according to logical and/or physical proximity) and scant information about distant servers, thereby avoiding both the extensive information exchange of highly informed network architectures and the inefficiency of uninformed routing algorithms.

Abstract: A distributed component model for creating a scalable and available distributed application is disclosed. The distributed component model provides for an application schema to be declaratively defined to include a module having a component. The schema includes a corresponding definition construct in a technology agnostic manner. The corresponding definition construct is declaratively defined to include metadata to control scaling and availability.

Abstract: A computer user may use a computing environment comprising a set of computers that respectively feature a web browser having a browser cache containing many types of data objects, including application resources and user-generated data files. However, the contents of a browser cache significantly contribute to the computing environment of a computer, and the computing environments presented by each computer may diverge, providing an inconsistent computing environment. Instead, the contents of browser caches of the computers comprising the computing environment may be synchronized across computers. Additionally, the browser cache may be synchronized with the other data objects of a computing environment (such as relevant portions of the filesystem); the synchronizing may be implemented as an out-of-browser process executing independently of the applications, and even when the browser is not executing; and the synchronization may be exposed through a programmatic access with which web applications may interact.

Abstract: A server set may provide a document service to various clients in view of considerations such as availability, fault tolerance, flexibility, and performance. Presented herein are document service architectures that involve partitioning the document set into at least two document ranges, and assigning the respective document ranges to an agent that is deployed to at least one assigned server. A request to apply an operation to a selected document may be fulfilled by identifying the document range of the document; identifying a selected server of the server set that hosts the agent to which the range is assigned; and forwarding the request to the selected server. In some variations, servers may retain detailed information about neighboring servers (e.g., according to logical and/or physical proximity) and scant information about distant servers, thereby avoiding both the extensive information exchange of highly informed network architectures and the inefficiency of uninformed routing algorithms.

Abstract: A method of creating an application definition for a distributed application is disclosed. Constructs corresponding with a schema of the distributed application are defined in a declarative and technology agnostic manner. The constructs include the application definition, a module definition, and a component definition. Each construct includes metadata.